Reduction in the amount of treated waste liquor has been intensively required recently from the point of view of environmental preservation and space saving in the field of medical treatment. It is therefore necessary to provide a technique concerning photosensitive heat development photographic materials which are used for medical diagnostic and photographic techniques and each of which can be exposed to light more efficiently by a laser imager so that a clear black image can be formed with high resolution and high sharpness. In these photosensitive heat development photographic materials, use of solution treating chemicals can be eliminated so that a heat developing system easier and not spoiling the environment can be provided to customers.
Although there is the same requirement in the field of general image-forming materials, a cold dark image is preferred as the medical image from the point of view of easy diagnosis as well as a high quality image excellent in sharpness and graininess is required because delicate depiction is required of the medical image. Although various hard copying systems such as an inkjet printer, an electrophotographic system, etc. using pigments and dyes are available as general image-forming systems, there is no satisfactory system currently used as a medical image output system.
On the other hand, a recording apparatus using a dry system not requiring any wet process has attracted public attention in recent years. In this type recording system, a film of a photosensitive and heat-sensitive recording material (photosensitive heat-sensitive recording material) or a heat development photosensitive material is used. This material will be hereinafter referred to as “heat development recording material” or “heat development photosensitive material”. In the recording apparatus using a dry system, a laser beam is applied (scanned) on the heat development recording material in an exposure portion to form a latent image. Then, in a heat developing portion, the heat development recording material is brought into contact with heating means to perform heat development. Then, the heat development recording material is cooled slowly and cooled. Then, the heat development recording material on which the image has been formed is ejected from the apparatus. In the dry system, the problem of waste liquid treatment can be solved compared with the wet process.
For example, the aforementioned thermal image-forming systems using organic silver salt have been described in specifications of U.S. Pat. Nos. 3,152,904 and 3,457,075 and “Thermally Processed Silver Systems” (Imaging Processes and Materials) Noblette, the eighth edition, written by B. Shely, edited by Sturge, V. Walworth and A. Shepp, page 2, 1996. Particularly, the heat development recording material generally has a photosensitive layer in which a catalytic activity amount of photocatalyst (e.g. silver halide), a reducing agent and silver salt capable of being reduced (e.g. organic silver salt) are dispersed in a binder matrix and in which a color tone control agent for controlling the color tone of silver may be dispersed in the binder matrix if necessary. After image exposure, the heat development recording material is heated to a high temperature (e.g. 80° C. or higher) so that a black silver image is produced by an oxidation-reduction reaction between silver halide or reducible silver salt (functioning as an oxidizing agent) and the reducing agent. The oxidation-reduction reaction is accelerated by the catalytic action of the silver halide latent image produced by exposure. For this reason, the black silver image is formed in an exposure region. The heat development recording material has been disclosed in a lot of documents inclusive of U.S. Pat. No. 2,910,377 and Japanese Patent Publication No. 4924/1968, and a medical image-forming system using the heat development recording material has been developed (e.g. see Japanese Patent Laid-Open No. 2003-005337).
The heat developing apparatus provided as an image-forming system for medical treatment will be described with reference to FIG. 6.
In FIG. 6, the reference numeral 200 designates a heat development recording apparatus. The heat development recording apparatus 200 is an apparatus which uses a heat development recording material not requiring any wet developing process so that after the heat development recording material is exposed to a laser beam in a scanning exposure manner to form a latent image, the latent image is heat-developed to obtain a visible image, and then the heat development recording material is cooled slowly and cooled to the ordinary temperature. Basically, the heat development recording apparatus 200 has a heat development recording material supply portion A, an image exposure portion (laser recording unit) B′, a heat developing portion C, a slow cooling portion D, and a cooling portion E. The portions A to E are arranged successively in the named order in the carrying direction of the heat development recording material. The heat development recording apparatus 200 further has carrying means provided at important positions between the respective portions for carrying the heat development recording material, and a power supply/control portion F for driving and controlling the respective portions.
The heat development recording apparatus 200 is formed so that the power supply/control portion F is disposed in the lowermost stage, the heat development recording material supply portion A is disposed above the power supply/control portion F, and the image exposure portion B′, the heat developing portion C, the slow cooling portion D and the cooling portion E are disposed above the heat development recording material supply portion A. The image exposure portion B′ and the heat developing portion C are disposed so as to be adjacent to each other.
According to this configuration, an exposure process and a heat developing process can be performed in a short carrying distance, so that the length of the carrying path of the heat development recording material can be minimized to thereby shorten the time required for outputting one sheet of the heat development recording material. Both the exposure process and the heat developing process can be applied to one sheet of the heat development recording material simultaneously.
The heat development recording material supply portion A is a portion for supplying the heat development recording material to the image exposure portion B′ located in a downstream side in the carrying direction of the heat development recording material while taking out sheets of the heat development recording material one by one. The heat development recording material supply portion A includes three loading portions 10a, 10b and 10c, pairs of feed rollers 13a, 13b and 13c disposed in the loading portions 10a, 10b and 10c respectively, not-shown carrying rollers and not-shown carrying guides. The loading portions 10a, 10b and 10c form a three-stage structure. Magazines 15a, 15b and 15c in which sheets of heat development recording materials different in size (e.g. B4 size, half size, etc.) are stacked are inserted in the loading portions 10a, 10b and 10c respectively. Any one of the magazines 15a, 15b and 15c inserted in the loading portions 10a, 10b and 10c can be selected for use in accordance with the size and direction of the required heat development recording material.
Incidentally, the heat development recording material is processed into a sheet shape. Generally, a predetermined number of sheets of the heat development recording material are stacked (or bundled). For example, 100 sheets of the heat development recording material are stacked (or bundled). The bundle of sheets of the heat development recording material is packed in a bag, a belt or the like to form a package. Packages formed in this manner are put in the magazines respectively. The magazines are loaded into the respective stages of the heat development recording material supply portion A, respectively.
When a sheet of the heat development recording material is carried from the heat development recording material supply portion A to the image exposure portion B′ by a carrying guide 14b, the image exposure portion B′ exposes the sheet of the heat development recording material to a light beam L in the main scanning direction. Further, the sheet of the heat development recording material is carried in the sub scanning direction (i.e. carrying direction) substantially perpendicular to the main scanning direction, so that a desired image is recorded as a latent image on the sheet of the heat development recording material. The image exposure portion B′ will be described later.
Next, the heat developing portion C will be described.
The heat developing portion C is used for heating the heat development recording material of the type subjected to heat treatment. As the configuration shown in FIG. 6, the heat developing portion C includes a plurality of plate heaters 51a, 51b and 51c which are provided as bodies heated to a temperature necessary for processing the heat development recording material 3 and which are curved in the carrying direction of the heat development recording material so as to be arranged like a circular arc.
That is, as shown in FIG. 6, the heat developing portion C including the plate heaters 51a, 51b and 51c is formed so that the plate heaters 51a, 51b and 51c have concave surfaces respectively. The heat development recording material 3 can be slid while brought into contact with the concave surfaces of the plate heaters, so that the heat development recording material 3 can be moved relative to the concave surfaces. A supply roller 53 and a plurality of pressure rollers 55 also used for transmitting heat from the plate heaters to the heat development recording material 3 are disposed as means for carrying the heat development recording material 3 on this occasion. The pressure rollers 55 abut on the circumferential surface of a drum 52 and are driven to rotate by the rotation of the drum 52. Metal rollers, resin rollers, rubber rollers, etc. may be used as the pressure rollers 55. According to this configuration, because the heat development recording material 3 is carried while pressed against the plate heaters 51a, 51b and 51c, the heat development recording material 3 can be prevented from buckling. Ejection rollers 57 for carrying the heat development recording material are provided at a terminal end of the carrying path of the heat development recording material 3 in the heat developing portion C.
The heat development recording material 3 fed out of the heat developing portion C is slowly cooled by the slow cooling portion D while care is taken to prevent the heat development recording material 3 from getting wrinkled or curly.
Pairs of slow cooling rollers 59 are disposed in the slow cooling portion D so that a desired predetermined radius R of curvature is given to the carrying path of the heat development recording material 3. What is meant by this is that the heat development recording material 3 is carried with the predetermined radius R of curvature until the heat development recording material 3 is cooled to a temperature not higher than the glass transition point of the material. Because the radius of curvature is given to the heat development recording material intentionally in this manner, the heat development recording material 3 can be prevented from being curled excessively before the heat development recording material 3 is cooled to a temperature not higher than the glass transition point. In addition, the heat development recording material 3 can be prevented from being curled newly after the heat development recording material 3 is cooled to a temperature not higher than the glass transition point. Accordingly, the amount of curl can be prevented from varying.
The temperature of the slow cooling rollers per se and the temperature of the inner atmosphere of the slow cooling portion D are regulated. This temperature regulation is provided so that the state of the heat treating apparatus just after the start of the heat treating apparatus and the state of the heat treating apparatus after sufficient running are equalized to each other as sufficiently as possible to thereby reduce variation in density.
The heat development recording material 3 cooled to a temperature not higher than the glass transition point by the slow cooling portion D is carried to the cooling portion E by a pair of slow cooling rollers 59 provided in the neighborhood of the outlet of the slow cooling portion D.
Cooling plates 61 are provided in the cooling portion E. In the cooling portion E, the heat development recording material 3 is further cooled to a temperature which does not cause a scald of the human hand when the human hand touches the heat development recording material 3. Then, the heat development recording material 3 is ejected to an ejection tray 16 by a pair of ejection rollers 63.
A heat development photosensitive material or a photosensitive heat-sensitive recording material can be used as the heat development recording material. The heat development photosensitive material is a recording material which can be used in such a manner that an image is recorded (exposed) by a light beam (such as a laser beam) and then colored by heat development. The photosensitive heat-sensitive recording material is a recording material which can be used in such a manner that an image colored by heat development after recorded by a light beam or an image recorded and colored simultaneously in a heat mode of a laser beam is fixed by light irradiation.
The laser image exposure portion B′ will be described here specifically.
FIG. 7 is a configuration view showing the schematic configuration of a sub scanning carrying portion for carrying a sheet of the heat development recording material and a scanning exposure portion in the laser image exposure portion B′.
The laser image exposure portion B′ is a portion for performing light beam scanning exposure so that the heat development recording material is exposed to a light beam. The laser image exposure portion B′ includes: a sub scanning carrying portion (sub scanning means) 17 having an anti-fluttering mechanism for carrying the heat development recording material while preventing the heat development recording material from fluttering relative to the carrying surface; and a scanning exposure portion (laser irradiation means) 19. The scanning exposure portion 19 scans a laser (in the main scanning direction) while controlling the output of the laser in accordance with image data provided separately. On this occasion, the heat development recording material is moved in the sub scanning direction by the sub scanning carrying portion 17.
The sub scanning carrying portion 17 has: two drive rollers 21 and 22 having axes arranged substantially in parallel to the main scanning line of the applied laser beam L so as to be opposite to each other with respect to the main scanning line; and a guide plate 23 disposed opposite to the drive rollers 21 and 22 and provided for supporting the heat development recording material 3. The guide plate 23 has slope portions 25 and 26, and a presser portion 29. The slope portions 25 and 26 are provided on the outside of the drive rollers 21 and 22 arranged side by side so that the heat development recording material 3 inserted between the guide plate 23 and each of the drive rollers 21 and 22 is distorted along a part of the circumferential surface of each drive roller. The presser portion 29 has a nearly horizontal surface which is provided between the drive rollers so that the nearly horizontal surface abuts on the heat development recording material while receiving elastic repulsive force caused by distortion of the heat development recording material.
The heat development recording material 3 enters the presser portion 29 while slipping down the slope portion 25, and passes through the presser portion 29 provided as a nearly horizontal surface. In this manner, the carrying path of the heat development recording material 3 is formed. The drive roller 21 provided opposite to the guide plate 23 gives force for carrying the heat development recording material 3.
The slope portion 25 is provided as an inclined surface which is bent at the boundary between the slope portion 25 and the presser portion 29 and connected to the presser portion 29. The crossing angle Φ between the slope portion 25 and the presser portion 29 is selected to be in a range of from 0° to 45°. The slope portion 26 on the downstream side in the carrying direction is formed in the same manner as the slope portion 25. The slope portion 26 is provided as a surface inclined at the crossing angle Φ to the presser portion 29. Incidentally, one inclined surface bent with a crossing angle Φ higher than 0° may be provided at least on the upstream side in the carrying direction.
When drive force of drive means such as a motor not shown is applied on the drive roller 21 through transmission means such as a gear, a belt, etc., the drive roller 21 rotates clockwise in FIG. 7. Incidentally, the drive roller 22 having the same configuration as that of the drive roller 21 is provided in the boundary between the slope portion 26 and the presser portion 29 for ejecting the heat development recording material 3.
The drive roller 21 will be described by way of example. The drive roller 21 is disposed opposite to a bent portion 31 which is the boundary between the presser portion 29 and the slope portion 25. FIG. 8 is a partly enlarged side view typically showing the position of the drive roller 21 relative to the guide plate 23. As shown in FIG. 8, the drive roller 21 is preferably disposed so that a line M passing through the bent portion (angular change point) 31 of the guide plate 23 and bisecting the inner angle (180°-Φ) of the guide plate 23 passes through the center of the drive roller 21. Incidentally, the relation between the diameter of the drive roller 21 and the length of the guide plate 23 is not particularly limited.
The drive roller 21 is also disposed so that a predetermined gap G is formed between the circumferential surface of the drive roller 21 and the guide plate 23. The gap G is preferably selected to be in a range of from t to 10 t (t≦G≦10 t) in which t is the thickness of the heat development recording material 3.
When the guide plate 23 is provided as a heat development processing portion, the surface of the guide plate 23 may be covered with fibers so that heat given from the heated guide plate 23 to the heat development recording material 3 can be optimized. In this case, the gap formed between the circumferential surface of the drive roller 21 and a front end of each fiber may be apparently zero because the recording material is carried while pushing down the front end of each fiber (see FIG. 7).
In the configuration of the sub scanning carrying portion 17, when the heat development recording material 3 enters the sub scanning carrying portion 17 at a front end of the slope portion 25, the front end of the heat development recording material 3 is put between the guide plate 23 and the drive roller 21. On this occasion, because the guide plate 23 is bent so that a predetermined angle Φ is formed between the presser portion 29 and the slope portion 25, the heat development recording material 3 is distorted when the heat development recording material 3 shifts from the slope portion 25 to the presser portion 29. This distortion generates elastic repulsive force in the heat development recording material per se. The elastic repulsive force causes predetermined frictional force between the heat development recording material 3 and the drive roller 21. As a result, carrying drive force is surely transmitted from the drive roller 21 to the heat development recording material 3, so that the heat development recording material 3 is carried. Incidentally, the coefficient of friction of the drive rollers 21 and 22 is larger than the coefficient of friction of the recording material contact surface of the guide plate 23.
The inclination angle Φ of the slope portion 25 (26) depends on the rigidity of the heat development recording material 3. When, for example, an imaging plate (IP) used in FCR9000 (trade name, sold by Fuji Photo Film Co., Ltd.) or an aluminum plate which is a photosensitive planar printing plate is used as the heat development recording material 3, the inclination angle Φ becomes low because the rigidity of the imaging plate or the aluminum plate is high. When, for example, a heat development recording material (using a film base) or a silver salt photosensitive material (using resin coated paper) is used as the heat development recording material 3, the inclination angle Φ becomes high because the rigidity of the heat development recording material or the silver salt photosensitive material is low. The inclination angle Φ depends on the rigidity of the heat development recording material 3. When, for example, a film base 175 μm thick is used as the heat development recording material 3, it is preferable that the inclination angle Φ is selected to be in a range of from 10° to 30°, and that the gap G is selected to be in a range of from 1 t to 5 t.
Also when the heat development recording material 3 is ejected from the guide plate 23 by the slope portion 26 and the drive roller 22, elastic repulsive force based on bending of the heat development recording material 3 causes generation of predetermined frictional force between the heat development recording material 3 and the drive roller 22 so that the heat development recording material 3 can be carried surely.
In the presser portion 29, the heat development recording material 3 is pressed against the presser portion 29 by the elastic repulsive force of the heat development recording material 3 so that the heat development recording material 3 can be prevented from fluttering relative to the carrying surface, that is, from fluttering vertically. When the laser beam L is applied on the heat development recording material 3 between the drive rollers, good recording free from displacement in exposure position can be performed.
On the other hand, the scanning exposure portion 19 is formed so that the laser beam L modulated according to an image signal is deflected in the main scanning direction and made incident on a predetermined record position X. As shown in FIG. 7, the scanning exposure portion 19 has: a laser beam source 35 for emitting a laser beam of a narrow wavelength band (wavelength: 350 nm to 900 nm) according to the spectral sensitivity characteristic of the heat development recording material; a recording controller 37 for driving the laser beam source 35; a cylindrical lens 39; a polygon mirror 41 serving as a beam deflector; an fθ lens 43; and a cylindrical lens 45 for trailing edge.
Incidentally, various optical members such as a collimator lens for shaping the laser beam emitted from the laser beam source 35, a beam expander, a surface drop correction optical system, an optical path adjusting mirror, etc. as disposed in a known light beam scanning exposure apparatus may be disposed in the scanning exposure portion 19 as occasion demands. Incidentally, the recording beam diameter of the laser beam applied on the heat development recording material 3 is selected to be in a range of from φ50 μm to φ200 μm. Particularly, the recording beam diameter in the sub scanning direction is preferably selected to be smaller to reduce the region of interference.
An exposure method is used here so that image recording is performed by pulse width modulation. The recording controller 37 drives the laser beam source 35 to perform pulse width modulation according to a recorded image so that a laser beam pulse-width modulated according to the recorded image is emitted from the laser beam source 35. The laser beam L emitted from the laser beam source 35 is deflected in the main scanning direction by the polygon mirror 41. The deflected laser beam is adjusted by the fθ lens 43 so as to be focused in the record position X. The optical path is selected by the cylindrical mirror 45. In this manner, the laser beam is made incident on the record position X at a predetermined incidence angle θi. That is, the laser beam L is applied on the heat development recording material 3 in the condition that the incidence angle θi of the laser beam L is inclined at an angle of from 4° to 15° in the sub scanning direction from a line normal to the heat development recording material 3 with respect to a plane parallel both to the normal line and to the sub scanning direction (carrying direction).